Stackable step stool



FIG. 1 is a top view of a stackable step stool embodying the design of the present invention;

FIG. 2 is an end view of the stackable step stool illustrated in FIG. 1;

FIG. 3 is a bottom view of the stackable step stool of FIG. 1;

FIG. 4 is a side view of the stackable step stool of FIG. 1; and,

FIG. 5 is a perspective view of multiple stackable step stools in accordance with the present invention.

The broken lines in FIG. 5 are for environmental purposes only and form no part of the claimed design. 

The ornamental design of a stackable step stool, as shown and described. 